Purity Charts
Purity may be expressed as fineness, percentage, or gold karats. Converting between them prevents confusion when comparing bullion, jewelry, and historic coins.
In This Guide
Purity Conversion Chart
| Fineness | Percentage | Gold Karat Equivalent | Common Example |
|---|---|---|---|
| .9999 | 99.99% | 24K (approximately) | Modern gold and silver bullion |
| .999 | 99.9% | 24K (approximately) | Many silver rounds, bars, and coins |
| .958 | 95.8% | 23K | Early silver Britannias |
| .925 | 92.5% | — | Sterling silver |
| .9167 | 91.67% | 22K | Gold Eagles, Krugerrands, Sovereigns |
| .900 | 90% | 21.6K | Historic U.S. gold and silver coins |
| .750 | 75% | 18K | Gold jewelry |
| .585 | 58.5% | 14K | Gold jewelry |
| .417 | 41.7% | 10K | Gold jewelry |
| .400 | 40% | — | 1965–1970 Kennedy half dollars |
| .350 | 35% | — | U.S. wartime nickels |
How Fineness Works
Fineness states precious-metal parts per thousand. A .999 product is 999 parts precious metal in 1,000, or 99.9%. A .900 coin is 90% precious metal.
How Karats Work
The karat system divides gold purity into 24 parts. Divide the karat number by 24 to obtain the gold proportion: 18K is 18/24, or 75% gold.
Calculate Fine-Metal Weight
Multiply gross weight by purity as a decimal. Ten grams of 14K gold at approximately .585 fineness contains about 5.85 grams of gold before refining losses or assay adjustments.
Marks Are Not Proof
Stamps can be false, worn, altered, or interpreted incorrectly. Plated items may carry confusing marks, and testing must suit the object.
- Do not confuse karat with gemstone carat.
- Do not treat color as a purity test.
- Do not round too early in a high-value calculation.
- Do not damage collectible pieces with destructive testing.
Frequently Asked Questions
What does .9999 mean?
It means 99.99% precious metal, or 9,999 parts in 10,000.
Is 22K gold the same as .9167?
Approximately yes: 22 divided by 24 equals 91.67%.
Does higher purity always mean higher value?
At equal gross weight it means more precious metal, but total weight, premium, rarity, condition, and demand also affect price.
Related StackUlator Tools
Related Resources
Resource Navigation
Helping stackers make smarter decisions.
Purity becomes useful only when paired with accurate weight and a trustworthy identification of the object.